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    <script>
        var arr = [['a','b','c'],['d','e','f',]['g','h','i'],['j','k','i']];
        var res = [];
        for(var i =0;i<arr[0].length;++i){
            res[i] = [];
            for(var j =0;j<arr.length;++j){
                res[i][j] = arr[i][j];
            }
        }
        console.group('转置前')
        console.log(arr);
        console.groupEnd();
        console.group('转置后');
        console.log(res);
        console.groupEnd();
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